Lubricant containing a metal derivative of a hydroxyarylakyl polaymine and a metal dithiocarbamate



United States Patent LUBRICANT CONTAINING AMETAL DERIVATIVE "OFAZHYDROXYARYL'ALKYL POLYAMINE 'AND A METAL 1 DITHIOCARBAMATE Frederic C.'McCoy and James-M. Cafirey,.lr., Beacon,

N. Y., and William RwHencke, Old Tappan, N. J., assignors to The Texas Company, New York, N. .Y., a corporation of Delaware -'No Drawing. App'lication July 26, '1952, Serial N 0.. 301,162

3 Claims. (C].'25233.6)

The present invention relates to improved lubricating tcompositions obtainedby means of a new combination'of .additives. More particularly, the invention relates ".to mineralslubricating oils containingmetal derivatives of .hydroxyarylalkyl polyamines in conjunction with metal .dithiocarbamates.

Whenhydrocarbo'n :oils are employed, as lubricants in internal combustion engines, .theyttend to undergo .oxidationiandother.deterioration under the severe conditions-to which theyare subjected, including high temperaturesfor dongperiodsof-time and the presence of catalytic metal :surfaces. As :3. :result of this deterioration, acids are produced which are corrosive to the bearings. and'other engine ,parts, and gums and sludges are formed which s'causeringsticking and .otherwise reduce the efiiciencytof operation. of' the engine. It:is, therefore, commonapracttice to add to lubricating voils :small amounts 10f com- ;pounds which have the property of imparting improved oxidation stability and/r anti-corrosiveness, and ;-also compounds of the detergent type, which act to reduce the formation of gums and sludges or to disperse and alter the character thereof so .as to reduce theforma- 'ti-on of varnish-like deposits upon the lubricated engine parts.

Howevenmany additives which are employed to improve certain properties of a lubricatingoil have .been found'to exert a deleterious effect upon other properties ofthe'oil, and -also the effectiveness of an .additive .is "frequently diminished or destroyed when it is employed in a lubricating oil together with other additives .of differ- =ent"chemical type. Since a catalytic .elfect is involved between the additives themselves as 'well :as between the additives and theoil; the elfect 'obtainable'by the use .of "two or more additives in combinationcannot'be predicted on "the basis of their separate etfects in lubricating compositions.

It has now'been 'f0und,'in accordance with the pre sent invention, 'that lubricating compositions of very special properties, including excellent oxidation :resistance and' an'ti-corrosiveness -to metals in addition to very superior detergency characteristics, are obtainedby adding to *hydrocarbon lubricating oils a minor proportion of a metal "derivative'of a hydroxyarylalkyl'polyamine, and a minor "proportion of a metal salt of a hydrocarbon-substituted dithiocarbamate.

"-By the'cooperative elfect of'the above additives a superior detergency is producedyand in addition the oxidation tendency' and corrosiveness of the composition are'efiectively inliibited. "The oxidationinhibiting action of the "ditl'iiocarbamate involves an inhibiting 'e'fiect upon the hydroxyarylalkyl polyamine derivative, since compounds 2752,31 l .Batenteddune 26, 1956 ice of the lattertype :are"norma1ly ,strong pro-oxidants in lubricating'compositions. The'e'fiectiveness ofthe dithiocarbamatesasfbothcxidation and corrosion inhibitors in these lubricating "compositions containing -hydroxyaryl- 'alkyl polyaminedeiivatives:is-very unexpected in view of the ineifectivenessfor-thispurpose'of alarge number of other compounds commonly employed as oxidation and corrosion inhibitors in lubricating compositions, including various'o'ther sulfur-containing"compounds '=The metalderivatives of hydroxyarylalkyl polyamines contemplated *by this invention are the metal derivatives of condensation pro'ducts disclosed-in'U. S. 2,353,491,

and also =the corresponding hydroxy=metal and alkoxymetal derivatives of such" condensation-products, wherein= thealkoxy group containsfrom '1' to 5 carbon atoms, -as :disclosed and-claimedin-the-copending application of H. 1). Kluge :an'd F. 'W.-Moore,'=SerialNo. 287,266, filed May 1-0, "19 52,--now.*PatentNo. 2,725,357. These compounds are-obtained by-interreacting a hydroxyaromatic compound with -ansaliphatic aldehyde andwith'an aliphatic -polyamine containing at. least two reactive, i. e., primary or secondary; amineagroupg so asto form a condensation "product, =and then further reacting the condensation prod- "uct-"thus-'obtaine'd so as to replacethe hydroxyl hydrogen with a membevof the'ggroup consisting'of metal, hydroxymetal-groups and lower alkoxy-metal groups. "The hy- -droxyarornatic -compoundgprferably contains an aliphatic hydrocarbon-group ofsufiicient size to impart oil-solubil- --ity to-t he final product. While either monoor polynuelear "hydroxyaromatic 1 compounds I may be employed in forming the condensation products,-as discussed inthe above-cited *patent, thehydroxyaromatic compound employed 'ismost suitablyyphenol, containing at least one aliphatic hydrocarbon group containing from about 5 to BO-carbon atoms.

l he product obtained by -the above 'condensationre- "action has been found' by-ana'lysisto' consist principally of compounds wherein one hydrogen attached'to-each'nitrogenaatom of the'lprimaryor secondary amine'groups is replaced by "a $hydroxyarylalkyl group, with smaller :amounts of both -hig'her and lowercondensation' products. =Forexample, when ethylenefiiamine is employed as :the ramine-reactant,the-product consists predominantly of TN,Nibis (hydroxyarallq'l) lg2 diamines. Informing the .additivefifor:use according to this invention, the condensation product is preferably converted directly to the metal "derivativegalthoug'h a prior-separationmay'be carried out wit desired to remove zanyhigher or lower condensation products. 7

Because ofithe generally --superior -detergency character- -.istics of compounds o'f the-=alkaline earth metals and zinc, the metaliemployed in forming the above metal'deriva- .tivesis preferablyzchosemfrom this group, although other metals such as' the' alkalh-metals, -tin, lead, etc., maybe employed if desired. With'partieular advantage-when the compounds *aretobecrnployed as additives where the character 'o'f'the-combustion-chamber deposits is an im- "portant consideratiomithe'metal is chosenjromthe group consisting of magnesium and zinc. 'Forregular-heavy duty motor '0ils,'howeve r, theiheavier ,metals "such as calcium and barium mayibe suitably employed.

The metal 'dithiocarbamates which .are employed as .the second component ,of the additive combination of ,our invention are p'olyvalent metal salts of organic-substituted 'dithiocarbamic acids, such as described for example in U. S. 2,400,106. They are preferably polyvalent metal salts of aliphatic hydrocarbon-substituted dithiocarbamic acids, wherein the aliphatic hydrocarbon groups contain a total of at least 8 carbon atoms. Compounds of this class wherein the metal is a member of the group consisting of the alkaline earth metals and zinc, and particularly of the group consisting of magnesium and zinc, are especially desirable. As examples of suitable compounds of this class may be mentioned zinc dibutyl dithiocarbamate, tin diamyl dithiocarbamate, zinc di(2-ethylhexyl) dithiocarbamate, calcium octyl-butyl dithiocarbamate, magnesium methyl-octyl dithiocarbamate, aluminum dioctyl dithiocarbamate, zinc petroleum base dithiocarbamates, nickel dicetyl dithiocarbamate, and so forth.

In addition to the compounds discussed above, the lubricating compositions of this invention preferably contain also an additive selected from the class of compounds consisting of polyvalent metal salts ofalkylated hydroxyaromatic monocarboxylic acids, as disclosed for example in U. S. 2,477,913. The hydroxyaromatic monocarboxylic acids may be either monoor poly-nuclear, such as for example aliphatic hydrocarbon substitutedsalicylic, ortho hydroxy naphthoic and anthracene ortho hydroxy carboxylic acids. Of the polyvalent metals which may be employed to form the salts of these acids, preference is given to metals of the group consisting of the alkaline earth metals and zinc, and particularly to magnesium and zinc. As particularly suitable compounds of this class may be mentioned the calcium, barium, magnesium, and zinc salts of alkyl (C540) salicylic acid. If desired, these salts may be partially in the form of their inner ring salts, as described in U. S. 2,293,419.

The compounds of the above described classes of lubricant additives may be employed in hydrocarbon lubricating oils in varying amounts, ranging from very small amounts up to amounts representing the limits of their solubilities. For ordinary purposes, the amount of each additive employed will lie within the range of from about 0.1 to about 5.0 per cent, and preferably within the range of from about 0.25 to about 2.0 per cent by weight of the lubricating composition.

The hydrocarbon oils compounded according to this invention will usually be petroleum fractions of lubricating viscosity, including highly refined and moderately refined oils from paraffinic, naphthenic and mixed base crude oils. However, synthetic oils, such as various polymer oils of lubricating viscosity, may also be employed if desired.

The superior lubricating properties obtained by use of the additive combinations of our invention have been demonstrated in numerous tests, including both laboratory bench tests and engine tests. Results obtained upon lubricating oils containing typical compounds of each of the hereinabove described classes of compounds in the combinations contemplated by our invention are described in the following examples.

As representative of the class of additives consisting of metal derivatives of hydroxyarylalkyl polyamines, the magnesium, methoxy-magnesium and barium derivatives of condensation products obtained by interreacting alkyl phenols with formaldehyde and with ethylene diamine were employed in these tests. The alkyl phenols employed comprised chiefly para-alkyl substituted phenols, which upon condensation with ethylene diamine formed N,N'bis(2 hydroxy-5 alkyl-benzyl)-l,2diamino ethanes. The magnesium and methoxy-magnesium derivatives of these compounds were obtained as described in the aforementioned application of Kluge and Moore, Serial No. 287,266, by first interreacting an alkyl phenol with formaldehyde and with ethylene diamine, and then treating the condensation product thus obtained with magnesium methylate, employing equimolar proportions of condensation product and magnesium methylate to obtain the normal magnesium salt and at least 2 mols of magnesium methylate per mole of condensation product to obtain the methoxy-magnesium derivative. As described in the examples given in the above application, the condensation reaction was carried out by adding the reactants together in an ethanol solution while the temperature was maintained below about F. and then refluxing for several hours to complete the reaction, employing approximately equimolar proportions of alkyl phenol and formaldehyde and about one half mol proportion of ethylene diamine. The barium derivative was prepared from a condensation product obtained as described above by reacting the condensation product with barium hydroxide in benzene solution, employing equimolar proportions of condensation product and barium hydroxide.

The dithiocarbamate salt employed in the tests was a commercial zinc dibutyl dithiocarbamate, which is sold by the R. T. Vanderbilt Co. under the trade name of Butyl Zimate. This product had a melting point of 106 F., a sulfur content of 28.25 per cent and a zinc content of 14.3 per cent.

The zinc alkyl salicylate which was employed in the tests was obtained by carboxylating an alkyl phenol and then converting the alkyl salicylic acid thus obtained to the zinc salt by reacting it with zinc acetate,

The alkyl phenol employed in the carboxylation was a product having a hydroxyl number of 135 and a molecular weight of 413, indicating that it contained an average of 23 alkyl carbon atoms per molecule. The carboxylation was carried out by reacting the sodium salt of this alkyl phenol with carbon dioxide under 300 p. s. i. g. pressure and at a temperature of 325 F. until the phenol was substantially entirely reacted. The reaction of the alkyl salicylic acid with zinc acetate was carried out by heating the reactants together in xylene solution under reflux, employing one mole of zinc acetate per two moles of alkyl salicylic acid, and thereafter distilling off the water and/ or acetic acid of reaction and the solvent. The product, which was finally obtained in the form of a 25 per cent solution of the zinc alkyl salicylate in a lubricating oil of 300 S. S. U. viscosity at F., analyzed 1.74 per cent zinc, as compared with the theoretical value of 1.66 per cent.

EXAMPLE l.CORROSION TEST Table I below gives the results obtained in the Mac- Coull Corrosion Test upon a mineral lubricating oil containing the additive combinations of our invention, comparatively with those obtained upon the same oil containing the additives of these combinations separately and also in combination with various other additives. This test is an empirical test designed to show the corrosiveness and oxidation stability of a lubricating oil under the bearing lubrication conditions existing in an internal combustion engine. The procedure is fully described in SAE Transactions, v. 50, pp. 338-345 (August 1942). Briefly, it comprises rotating a copper-lead bearing specimen at high speed in a sample of the test oil maintained at 350 F. in the presence of catalytic metal surfaces and of air, and determining the loss in weight of the bearing specimen at two hour intervals up to ten hours. The mineral lubricating oil employed was a lowsulfur oil having an SUS viscosity at 100 F. of about 518, obtained by solvent refining and clay and acid treating a wax distillate fraction from a paraflin base crude oil. It contained 1.76 percent of a mixture of high molecular weight methacrylate polymers employed in lubricating oils as viscosity improving agents.

For convenience, derivatives of phenol-formaldehydeethylene diamine condensation products are referred to in the tables as derivatives of N,N bis(hydroxy-alkylbenzyl)-1,2-diamino ethanes, which were found by analysis to comprise the chief component of these condensation products.

Whereverpossible, the values for; duplicate runs on each" lubricating composition have been given ini'the tables; as an indication of the reproducibility and reliability of the results.

TABLE I MacCaull corrosion testat 350 F.

Weight N eutral- Detergent Inhibitor Loss, ization No.

mg./l0 hrs Used oil None. 141; 160 13.2; 12.5 1% Mg derivative of 63; 42 13.3; 13.2 N N'bis(hydroxyalfryl on benzyl)-1,2- diamino ethane. 1% Zn a1kyl.sa1icylate .do 69; 61 5.3; 5.2 None 1% ButylZimate 6; 4 (115) l 1.1 (6.7) 1 1% Mg derivative of None 142; 125 13.3; 12.7

N ,N' bis(hydroxy-a1kyl (On) b y mino ethane-+05% Zn alkyl salicylate.

Do 0.5% ButylZimate. 1; 1 0.08 Do 17S autolube 394- 108;145 7.7; 7.8 1% Methoxy-Mg deriva- None 22 5.4; 5.5

tive of N,Nbis (hydroxyalkyl (O19) benzyl)-1, 2-diamino ethane. 25 1% Methoxy-Mg deriva- 0.5%ButylZimate; 2; 9 0.44

tive of N,Nbis (hydroxyalkyl (Cu) benzyl)- LZ-diamino ethane. 1% Methoxy-Mg deriva- None 105; 112 10.2; 10.9

tive of N,Nbis(hydroxyalkyl. (022) benzyl)- 1,2.-diaminoethane+1% Zn alkyl salicylate. 1% Methoxy=Mgderiva1 '.---.do 79; 100. 10.5

tive oiN,Nbis(hydroxyalkyl (C benzyl)1, 2-diaminoethane+0.5%. Zualkylsalicylate.

Do Lubrizol'747 86; 25 7.7; 719 1% Mcthoxy-Mg deriva- .0;5%Butyl=Zimate- 3; 2 0.77 alk.

tive of N ,Nbis (hydroxyalkyl- (On) benzyl) 1,2-diamino ethane 1% Zn alkyl salicylate; 1% Methoxy-Mg deriva- ....d0 1; 1 0.44

tive of N,Nbis (hydroxyalkyl {022) benzy1)- 40 1,2-d1am1no ethane 0.5% Zn alkyl salicylate.

Do 1% di- 2 -etahyl- 147; 131 10.4 hexyl ether of dithiodiglycol. Do 1% d1 2 ethyl- 100; 107 8.2; 8. 7

hexyl disulflde. Do 1% isophorone- 141; 132 6. 2; 5. 9

mercaptan condeilsatiouproduc Do 1% 2-ethyl-hexyl 96;98 8.8; 9. 2

thiocellosolve. Do 1% dibenzyl (11- 102; 71 7.9; 7. 7

sulfide. Do 1% 4- methyl -2 142; 131 10. 5; 11.0

tert. butyl 6 tert. amyl thiomethylphenol.

l 'A different base oil giving aweight loss of 115 mg. and a neutralization No. of 6.7 was used inthis test.

2 A commercial oxidation and corrosion inhibitorconsistm gof ox dation product of olefin-phosphorus pentasulfide-reaction produchobtamed from the Monsanto Chemical Co.

A commercial oxidation and corrosion inhibitor comprising the barium salt of an alcohol-P ss reaction product, obtamed'irom the Lubrizol Corp. 7

As shown by the above table, only a moderate improvement in the corrosion inhibiting properties of a minerallubricating oil was obtained by use of a metal derivative of a hydroxy-arylalkyl polyamine or of a metal salt of a hydroxyaromatic' acid, employedseparately. A very corrosive oil. substantially equivalentto the uncompounded oil, was produced when compounds of both of these classes of compounds wereemployed in combination. Furthermore, the corrosiveness of lubricating 011s containing these additives in combination was not inhibited by the use of a number-of other compounds commonly employed in lubricating compositions as oxidation and corrosion inhibitors, including various sulfur-containing compounds. However; by the addition of a small amount of a metal.dithiocarbamate to lubricating oils containing. a metalv derivative of a hydroxyarylzalkyi a c" polyamine, either alone or in combination with a metal hydroxyaromatic acid salt, lubricating oils of very exceptional anti-corrosiveness and oxidation stability were obtained.

EXAMPLE 2.DETERGENCY TESTS Table H below shows the detergency characteristics imparted to .a lubricating oil by use of the additive combinations of this invention, comparatively with the detergent eifectiveness of the same additives employed. separately. The Toettcher varnish test and the High Temperature Deposits Test of the table are bench tests which have been found to correlate well with the lacquer forming and the oil ring sticking characteristics of a motor oil in actual service. In the Toettcher varnish test, a- Weighed glass cylinder is immersed in a sample of. the test oil maintained at 350 F. and agitated by a centrifugal mixer. Copper baflles are also immersed in the test oil to act as oxidation catalysts. After 13 hours. the test is terminated and the glass cylinder removed, washed with pentane, dried and reweighed. The amount of varnish deposited on the cylinder is the difierence between the initial and final weights of the cylinder. Theneutralization number of the used oil is also determined. The High Temperature Deposits Test is carried out by re.- peatedly dipping an aluminum cylinder one inch in diameter'and three inches long, maintained at 525 F. into a beaker containing a sample of the test oil, for a period of 20 hours. The test specimen is then washed with pentane and dried, and the Weight of deposits fOllnd. by the increase in: weight. The test specimen is then brushed to remove loose deposits and reweighed to determine the amount of varnish-like deposits. A lubricating oil of the same type as that employed in the corrosion test of Example 1 was employed in these tests.

TABLE II Detergency tests High Temperature Deposits Test, 52' F.

Toettcher Varnish Test, 350 F.

Neutral deposits, mg.

ization N. Used 011 Weight of deposits, mg.

Toml herent None (base oil) 1% Mg derivative of N, N bis (hydroxy-alkyKC benzyl)-1, 2-diam1no ethane 1% Zn alkyl salicylate 0.5% Bnty1Zimate 1% Mg derivative of N,N bis (hydroxy-alkyl( Cu) benzyl)-1,2-diam1no ethane +05% Zn alkyl salioylate +05% Butyl Zimate 1% Methoxy-Mg derivative oi ,Nbis(hydroxy-alkyl (On) benzyh l 2-diamino ethane +05%. Zn alkyl salicylate +05% Butyl Zimate 1% Methoxy-Mg derivative of N,Nbis(hydroxy-alkyl (O22) benzyl) l 2- diamino ethane +05% Zn alkyl salicylate +0.75% Butyl Zimate 0; 0; 0. 1 0. 05 alk. 4 4

O. 2; 0.7 0.12 allr.

As shown by the data given in the above table,.,lubricating compositions obtained by use of additive corm binations of this invention had outstandingly superior detergency characteristics. The detergency efiect of the additives employed in combination was superior to that obtained by any of the additives employed separately, and in addition the oxidation tendency of the composition, including the oxidation-promoting eiiects of both the magnesium derivatives of N,N'bis(2 hydroxy-S- 7 alkyl(C2z)benzyl)1,2-diamino ethane and the zinc salicylate, were very effectively inhibited.

EXAMPLE 3.THE ENGINE TESTS In addition to the above laboratory tests, engine tests were carried out upon the compounded oils of this invention to determine their performance under actual operating conditions. These compounded oils were obtained by adding typical compounds of our additive combinations to a lubricating oil of the same type as that employed in the tests described in Examples 1 and 2.

Table II below gives the results obtained in the Lauson L-4 Engine Test. This test was carried out by employing the test oils to lubricate a single cylinder standard Lauson engine while it was operated for 40 hours at 1850 revolutions per minute, with the jacket temperature maintained at 200 F. and the sump temperature at 310 F. At the end of the run the engine was taken down and inspected for bearing weight loss and piston deposits. A bearing Weight loss of less than 200 m in this test is considered satisfactory and a loss of less than 100 mg. is considered excellent. The pistons were rated on a scale of from for a completely varnished piston to for a completely clean piston. A piston rating above 8 indicates an oil of satisfactory detergency, while a rating of 9 or more indicates an oil of very excellent detergency.

TABLE III Lauson L4 engine test Neutralization No. Used oil Bearing \Veight Loss, mg.

Piston Additive Rating As shown by the data given in the above table, a lubricating composition having both satisfactory detergency and anti-corrosiveness was obtained by the use of a small amount of a hydroxyarylalkyl polyamine metal derivative and a small amount of a dithiocarbamate salt in a lubricating oil. The data also show that, very unexpectedly, a pronounced synergistic effect upon both the detergency and the anti-corrosiveness ofthe lubricating composition under the conditions of this test were obtained when a small amount of metal salicylate was also added to the composition containing the above addi tive combination.

Table IV below also shows the superior detergency properties of the compounded lubricants of this invention when employed in the lubrication of a heavy duty diesel engine, in comparison with those of a commercial diesel oil of good grade. This test was carried out by operating a super-charged single cylinder 5% by 8 inch Caterpillar diesel test engine for 50 hours, with an engine speed of 900 revolutions per minute, a fuel-oil ratio of 0.055 and a crankcase oil temperature of 200 F. At the end of each run the power section of the engine was inspected for deposits and other conditions detrimental to engine operation, and rated by a demerit rating system. Accord- 8 ing to this system, a. rating of 183 is accorded-to the worst possible condition for total piston deposit demerits in this test, while zero represents a new or clean condition. For ring sticking, the worst possible condition would be assigned a rating of 240.

TABLE IV Caterpillar diesel engine test Demerlt Rating of Piston Assembly Neuitrallzat on Addmve Total pts- Rm No. Used ton I )testicklg oil D Demcms Demerits Commercial Diesel Oil 45 O 1.02 1% Methozy-Mg deri ative of N,N

his(hydroxy-alkyl(C22)benzyl) 1,2'diamino ethane +05% 111 yl salicylate +0.75% Butyl Zimate 23 0 U. 10 1% Mg Derivative of N,N bis (hydroxya-lkyl(Czz) benzyl)-1,2-diami.no ethane +05% Zn alkyl salioylete +05% Butyl Zimate l9 0 0. 0D 1.1% Ba derivative of N,N' blsthydroxy-alkyKGzz) benzyl)-l,2-diamino ethane +05% Zn alkyl snlieylate +0.5% Butyl Zirnate 38 30 0. 62

Table V gives results obtained upon a typical compounded oil of our invention in a 40-hour Chevrolet engine test designed to measure the varnish-forming properties of an oil under severe conditions. This test was carried out with a standard Chevrolet engine operated at a speed of 2,500 revolutions per minute and a crankcase oil temperature of 275 F., employing as the fuel an unleaded 420 F. end point thermally cracked naphtha. The oil employed in this test was a lubricating oil of the same type as described in connection with the previous tests compounded with 1% of the methoxy-magnesium derivative of N,Nbis(Z-hydroxy-S-alkyKCzz) -benzyl) -l,2- diamino ethane, 0.5% of Zn alkyl salicylate and 0.5% of Butyl Zimate.

TABLE v Chevrolet engine test Compounded Base Oil Oil Piston Skirt Deposits, mg 62 507 Oil Ring deposits, mg 126 772 Pan and cover deposits, rng.:

Acetone soluble 87 2, 176 Acetone insoluble 794 2, 546 CRO ratings:

Piston 10. 0 5. 5 Total 92 70 Used oil tests:

Neutralization numbe 55. 4 53. 8 40 hours 56. G 72. 3 Dissolved sludge, mg./1U g.-

0 hours None None 40 hours 20 422 Undissolved ludge, mg./1() g.

0 hours 13 None 40 hours 33 223 The data given in the above table show the very excellent detergency characteristics of a typical compounded lubricant of this invention obtained in actual operation of an internal combustion engine.

Obviously many modifications and variations of the invention, as hereinbefore set forth, may be made without departing from the spirit and scope thereof and, therefore, only such limitations should be imposed as are indicated in the appended claims.

We claim:

1. A lubricant composition comprising a major proportion of a mineral lubricating oil having admixed therewith about 0.1-5.0 per cent by weight based on the weight of the composition of the methoxy magnesium derivative of N,N'bis(2-hydroxy-5-alkyl( C1530)b6I1ZY1) 1,2 diamino ethane and about 0.15.0 per cent by weight based on the weight of the composition of zinc dibutyl dithiocarbamate.

2. A lubricant composition comprising a major proportion of a mineral lubricating oil having admixed therewith about 0.1-5.0 per cent by weight based on the weight of the composition of a compound chosen from the class consisting of magnesium and methoxy magnesium derivatives of N,N'bis(2-hydroxy-5-alkyl(C15 so)-benzyl-1,2-diamino ethane, about 0.1-5.0 per cent by weight based on the weight of the composition of zinc dibutyl dithiocarbamate and about 0.1-5.0 per cent by weight based on the Weight of the composition of zinc alkyl (C15 2o) salicylate.

3. A lubricant composition comprising a major proportion of a mineral lubricating oil having admixed therewith about 0.1-5.0 per cent by weight based on the weight of the composition of the methoxy magnesium derivative of N,Nbis(2-hydroXy-5-a1kyl(Cm-so)benzyl) 1,2 diamino ethane, about 01-50 per cent by weight based on the weight of the composition of zinc dibutyl dithiocarbamate and about 0.15.0 per cent by weight based on the weight of the composition of zinc alkyl (Cm- 0) salicylate.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A LUBRICANT COMPOSITION COMPRISING A MAJOR PROPORTION OF A MINERAL LUBRICATING OIL HAVING ADMIXED THEREWITH ABOUT 0.1-5.0 PER CENT BY WEIGHT BASED ON THE WEIGHT OF THE COMPOSITION OF THE METHOXY MAGNESIUM DERIVATIVE OF N,N''BIS(2-HYDROXY-5-ALKYL(C15-30)BENZYL) - 1,2 - DIAMINO ETHANE AND ABOUT 0.1-5.0 PER CENT BY WEIGHT BASED ON THE WEIGHT OF THE COMPOSITION OF ZINC DIBUTYL DITHIOCARBAMATE. 